You don’t stop stammering babes! Just keep practising speaking the alphabet pronounce every word properly! I’m 25 have had it all my life it’s got better over time to where no one knows I have one except myself but that can be hard too just know that you are not alone in this! Meditation is a must to control your breathing and push yourself to order food and push yourself to do more than you wouldn’t do like use the phone I swear it helps no matter how much nerves u have it works over time